The present invention relates to a light irradiating device, manufacturing method thereof and lighting apparatus using the light irradiating device, more particularly, the technology of achieving the improvement in the light irradiation efficiency and the improvement in the reliability of the device.
First, in case the light must be irradiated in great quantities, normally the electric lamp, etc. are employed. However, for the purpose of the reduction in weight, thickness, and size and the saving of electricity, sometimes the light emitting elements 2 are mounted on the printed circuit board 1, as showing FIG. 19.
The light emitting diode formed of the semiconductor is mainly employed as this light emitting element. But the semiconductor laser, etc. may also be employed.
The light emitting diode 2 has two leads 3, 4. One lead 3 is adhered to the back surface of the light emitting diode chip 5 (the anode electrode or the cathode electrode) with the solder, etc., while the other lead 4 is electrically connected to the electrode on the chip surface (the cathode electrode or the anode electrode) via the metal thin wire 6. Also, the transparent resin sealing member 7 for sealing the leads 3, 4, the chip 5, and the metal thin wire 6 is formed to be used as a lens.
Meanwhile, the electrodes 8, 9 for supplying the power supply to the light emitting diode 2 are provided to the printed circuit board 1. The above leads 3, 4 are inserted into the through holes provided in the printed circuit board 1, and the light emitting diode 2 is fixed/mounted onto the printed circuit board 1 via the solder, etc.
For example, the light irradiating device employing the light emitting diodes is explained in Japanese Patent Application Publication No. H09-252651.
However, since the above light emitting diode 2 is formed as the package into which the resin sealing member 7, the leads 3, 4, etc. are incorporated, there is the drawback such that the size of the packaged substrate 1 is increased. Also, since the radiating characteristic of the substrate itself is inferior, there is the problem such that the temperature rise is brought about as a whole. Therefore, there are the problems such that the temperature rise of the semiconductor chip itself is caused and thus the driving capability is lowered.
In addition, the light emitting diode chip 5 also emits the light from its side surface of the chip. Thus, there exists the light that is directed toward the substrate 1. However, since the substrate 1 is formed of the printed circuit board, there is the problem such that the highly effective emission in which all the lights are emitted upward cannot be achieved.
The present invention has been made in light of the above subjects, and provides a light irradiating device having the good radiation characteristic, that comprises a plurality of conductive paths that are electrically separated, photo semiconductor chips that are fixed onto desired conductive paths, and a resin for covering the photo semiconductor chips and serving as a lens to support the conductive paths integrally.
Also, there is provided a light irradiating device that comprises a plurality of conductive paths that are electrically separated by isolation trenches, photo semiconductor chips that are fixed onto desired conductive paths, and a resin for covering the photo semiconductor chips to fill the isolation trenches between the conductive paths and serving as a lens to support the conductive paths integrally while exposing only back surfaces of the conductive paths. Therefore, back surfaces of the conductive paths can be connected to the outside to eliminate through holes and thus the above subjects can be overcome.
In addition, there is provided a light irradiating device manufacturing method that comprises the steps of preparing a conductive foil and then forming conductive paths by forming isolation trenches, which are shallower than a thickness of the conductive foil, in the conductive foil except at least areas serving as the conductive paths, adhering respective photo semiconductor chips onto desired conductive paths, molding a resin serving as a lens to cover respective photo semiconductor chips and to fill the isolation trenches, and removing the conductive foil on a side on which the isolation trenches are not provided. Therefore, since the conductive foil to form the conductive paths is employed as the starting material, the conductive foil has the supporting function until the resin is molded, and the resin has the supporting function after the molding, the supporting substrate can be omitted and thus the above subjects can be overcome.
Further, there is provided a light irradiating device manufacturing method that comprises the steps of preparing a conductive foil and then forming a plurality of conductive paths by forming isolation trenches, which are shallower than a thickness of the conductive foil, in the conductive foil except at least areas serving as the conductive paths, adhering a plurality of photo semiconductor chips onto desired conductive paths, forming connecting means for electrically connecting electrodes of the photo semiconductor chips and desired conductive paths, molding a resin to cover the plurality of photo semiconductor chips and to fill the isolation trenches, removing the conductive foil having a thickness portion, on which the isolation trenches are not provided, and separating the photo semiconductor chips into an individual photo semiconductor chip by cutting the resin. Therefore, a large number of light irradiating devices can be mass-produced and thus the above subjects can be overcome.
Also, if the corrosion-resistant conductive film is formed in at least the areas, which serve as the conductive paths, of the surface of the conductive foil, this conductive film is left on the upper surface of the conductive foil like the visor when the isolation trenches are formed in the conductive foil. Therefore, the adhesiveness between the conductive foil and the resin can be improved when each light irradiating device is covered with the resin.
In addition, when the conductive foil is bent to surround at least the areas, to which the photo semiconductor chips are fixed respectively, of the conductive foil, such conductive foil is bent to have an inclination angle that enables the light emitted from the photo semiconductor chip to reflect upwardly. Therefore, the irradiation efficiency can be improved.
Further, the conductive foil is bent in the situation that the corrosion-resistant conductive film is formed on the conductive paths. Therefore, the gloss appears on the conductive film, and thus the irradiation efficiency can be much more improved.
Also, there are provided the step of removing the conductive foil on the side, in which the isolation trenches are not provided, up to a predetermined position after the light irradiating devices are covered with the resin to fill the isolation trenches, and then the step of separating the light irradiating devices that are covered with the resin. Therefore, respective light irradiating devices are not separated up to the final stage, and accordingly the conductive foil can be provided to respective steps as one sheet, and thus the workability becomes good.
Further, the resin is fixed by the transfer molding using the mold. Therefore, the workability can be improved and also the proper shape can be formed. Particularly, it is suitable for forming a lens shape.
Also, in the case that the individual light irradiating devices that are sealed with the resin are separated by the press machine, the process of removing the flash generated on the end portions of the light irradiating devices is not needed and thus the productivity can be improved.
Further, if the adhesiveness between the material of the conductive film and that of the insulating resin is lower than the adhesiveness between the material of the conductive foil and that of the insulating resin, the conductive film is formed on the conductive foil in the area smaller than the area served as at least the conductive path. Therefore, the area on the conductive foil where the conductive film does not covered, becomes large. Therefore, the adhesiveness between the conductive foil and the resin can be improved when light irradiating device is covered with the resin.